1. Technical Field
The present invention relates to a projector that displays, through projection or others, images formed on a liquid crystal panel, or others, other types of display units, and a light-emitting unit that emits illumination light for projection.
2. Related Art
In the projector of a previous type, light coming from a light source is directed to an optical system configured by a pair of microlens arrays, and then to a color separation system for color separation therein. The resulting color lights are directed to each corresponding optical path, and then to each corresponding liquid crystal panel so that the liquid crystal panels are illuminated. For more details, refer to Patent Document 1 (JP-A-11-64977).
In such a projector, a pixel area (corresponding to an effective area in the invention) formed to a liquid crystal panel is fixed in size (outline shape) depending on the liquid crystal panel in use. For projection of images varying in aspect ratio, the images are displayed within thus fixed outline shape of the pixel area. More in detail, the outside shape of a pixel area, i.e., length-to-width ratio, is generally fixed to be substantially 3:4. For display of any image having a length-to-width ratio of 9:16 within the outline shape of the pixel area, e.g., high-definition image with an aspect ratio of 16:9, the pixel area with a length-to-width ratio of substantially 3:4 (corresponding to an image with an aspect ratio of 4:3) is partially made unavailable in the vertical direction, i.e., no image is projected so that no light is passed therethrough. In this manner, the length-to-width ratio of 9:16, i.e., aspect ratio of 16:9, is implemented.
The problem with Patent Document 1 is that the illumination unit and the projection unit require the microlens array and the color separation system, whereby the illumination system is complicated in configuration.
Another problem comes up when any image of different aspect ratio is to be displayed or the purpose, even if the pixel area is partially modulated in the vertical direction and made unavailable for light transmission thereby, the portion corresponding to the unavailable image area is not turned to black in color after projected on the screen. The black is the color of light not to make the light pass therethrough. This i caused by the fact that the illumination light coming from the light source is directed to the entire pixel area of the liquid crystal panel, and as a result, the projected image is reduced in contrast or others.